Evaluating the resilience of semi-arid vegetation and ecosystem function during the late Holocene in the south-central Andes

超过30%的地球表面被归类为干旱土地。干旱地区容易受到降雨量微小变化的影响。依赖干旱土地的人也很容易受到降雨量和时间变化的影响。南美洲的安第斯山脉拥有世界上最极端的环境之一的干旱土地。预计该区域在未来几十年将经历更频繁的严重干旱，令人担忧其对现有自然资源和生计的影响。该项目的目标是调查超出历史记录的安第斯山脉干旱地区的气候和人类对生态系统的控制。这项研究旨在提高我们预测未来这些生态系统因气候变化和土地利用压力而发生变化的能力。该项目正在通过培训讲习班为早期职业科学家提供进行研究的培训机会。该项目还开展了一项国际合作，将科学家与玻利维亚萨哈马国家公园的土著团体和公园护林员联系起来。该项目产生的数据保存在新托玛古生态数据库和全球木炭数据库中。这项研究通过分析从啮齿类昆虫和泥炭地沉积岩芯中提取的化石植物材料，调查了安第斯旱地对气候、火灾和人类土地利用的适应能力。由此产生的数据被用来检验这样一个假设，即人类干扰加上气候变化导致自然生态系统的稳定性降低和恢复时间延长。结合来自虫洞和岩心的古生态信息以及直接来自考古记录的人为指标，可以重建生态系统动态。对玻利维亚安第斯山脉中南部的两个地点进行了研究。植被重建与粪便生物标志物和人类人口重建相结合，以评估过去人类土地利用变化的生态遗产。该项目有助于确定气候变化和人类活动之间的关系，以及过去几千年来干旱土地的弹性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Over 30% of the Earth’s surface is classified as arid lands. Arid lands are vulnerable to small changes in precipitation. People that rely on arid lands are also vulnerable to changes in precipitation amount and timing. The Andes Mountains of South America contain arid lands that are one of the most extreme environments in the world. The region is expected to experience more frequent severe droughts in the coming decades, causing concern about the impacts on available natural resources and livelihoods. The goal of this project is to investigate the climatic and human controls on ecosystems in the arid lands of the Andes beyond the historical record. This research aims to improve our ability to predict changes in these ecosystems in the future because of climate change and land-use pressure. This project is providing training opportunities for early career scientists to conduct research as well as through training workshops. This project is also developing an international collaboration to connect scientists with Indigenous groups and park rangers at the Sajama National Park in Bolivia. Data generated from this project are archived at the Neotoma Paleoecology Database and the Global Charcoal Database.This research investigates the resilience of Andean drylands to climate, fire, and human land-use through the analysis of fossil plant material recovered from rodent middens and peatland sediment cores. The resulting data are used to test the hypothesis that human disturbance coupled with changing climate leads to reduced stability and longer recovery times of natural ecosystems. Combining paleoecological information from middens and cores as well as anthropogenic indicators directly derived from the archaeological record allows reconstruction of ecosystem dynamics. Two sites in the southcentral Bolivian Andes are studied. Vegetation reconstructions are combined with fecal biomarkers and human demographic reconstructions to assess the ecological legacies of past changes to human-land use. This project helps determine the relationships between climate variability and human activities as well as the resilience of arid lands over the last few thousand years.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.